具有导热的竖环形封闭腔内自然对流数值研究

摘要

以中国实验快堆堆坑为计算原型，采用有限容积法对具有导热的竖环形封闭腔内自然对流进行了二维层流稳态数值研究。数值计算结果表明：在相同 Ra 条件下，平均 Nu 随曲率的增加而增加，随纵横比的增加而降低，但在低 Ra 区，平均 Nu 几乎不随纵横比变化；在低 Ra 区，竖环形封闭腔内换热方式主要是导热，当 Ra 大于某一临界值后，腔内对流换热的作用显著增强，并随 Ra 的增大逐渐占据主导。%Taking the pit of China Experimental Fast Reactor as the prototype,the finite volume method was adopted to conduct numerical simulation for a two-dimension lami-nar steady-state natural convection in vertical annular enclosed cavity.The results show that under the same conditions of Ra ,the average Nu increases with the curvature, while decreasing with the increase of the aspect ratio (ratio of height and gap in annular enclosed cavity).But in lower Ra zone,the average Nu has little change with aspect ra-tio and the heat conduction is dominant.After the Ra exceeds critical value,the heat convection makes a greater impact in cavity and then gradually holds the dominant posi-tions with the increase of Ra .